【作者】 彭建伟；

【导师】 孙玉学；

【作者基本信息】 大庆石油学院 ， 油气井工程， 2004， 硕士

【摘要】 目前，大庆油田所钻的水平井中使用的钻井液基本上为油基钻井液，其成本高，携带岩屑的性能较差，而且废弃钻井液如果处理不当，会造成环境污染。为此，开展了适用于大庆油田水平井的水基钻井液体系——MEG钻井液体系研究。在室内对MEG与油基乳化钻井液及盐水对地层的稳定性影响进行了实验对比，并分析了MEG对环境的影响。在此基础上筛选出与MEG配伍性好的处理剂，通过大量实验确定了MEG钻井液体系的最佳配方。实验研究表明MEG钻井液能够与泥页岩作用形成类似油基钻井液与泥页岩作用形成的半透膜。在半透膜的作用下，适当调整钻井液的活度小于地层水的活度，渗透压会使地层中的水向钻井液运移，避免或减少因钻井液向地层运移而产生的负面影响，对地层的稳定起到积极作用。MEG钻井液与地层作用的整个过程大致可以分为自由扩散作用、吸附作用和渗透作用三个作用阶段。这三种作用在钻井液与地层作用的整个过程中所起作用的重要程度不同，但有机地结合在一起共同起到稳定井壁的作用。由于这些作用与油基钻井液的作用相仿，某些学者将MEG钻井液称为仿油基钻井液。室内对比MEG钻井液体系和几种常用的水基钻井液体系表明，MEG钻井液体系在防塌、润滑、携屑和保护油气层等方面具有明显的优势。研制的MEG钻井液体系在室内对比分析的基础上在大庆油田进行了现场实验。室内和现场实验表明MEG钻井液流变性稳定，能够有效携带岩屑，清洗井眼，润滑性能良好，在钻井过程中能够有效稳定井壁，保护油气层，并且不会带来环境保护问题。这说明所研制的MEG钻井液体系能够很好地满足大庆油田水平井钻井的需要。更多还原

【Abstract】 The currently used drilling fluids in horizontal wells of Daqing Oil Field are mainly oil-based drilling fluids, which are high cost and have a poor solid carry capacity and may result in environmental problems because of the ineffective dispose of drilling waste. Therefore, a study is commenced to develop a water-based drilling fluid system (MEG drilling fluid system) that can satisfy the needs of horizontal well of Daqing Oil Field. The study begins with the compare of shale inhibition abilities between methyl glucoside(MEG) and oil-based emulsion-drill ing fluid and brine waters. Then, the environmental effect of MEG is analyzed. Afterwards, the compatibility of MEG and the additives is tested and the optimal MEG drilling fluid composition is got through trials and errors. The laboratory experiment shows that MEG drilling fluid/shale interface can provide a semipermeable membrane like the one provides by oil-based drilling fluid/shale interface. Under the function of semipermeable membrane, a reasonable adjust of the drilling fluid activity to be less than formation water activity will transfer water from formation to drilling fluid because of the existence of osmosis pressure. This will prevent or reduce the negtive effect resulted from the transfer of drilling fluid to formation and benefit the wellbore stability. The reaction process between MEG drilling fluid and formation may include diffusion, absorption and osmosis. These three reactions play different roles during the whole process, but entangle to maintain the wellbore stability. Because the reactions are similar to those of oil-based drilling fluid, some researchers name the MEG drilling fluid as pseudo oil-based drilling fluid. The compare between MEG drilling fluid system and some commonly used water-based drilling fluids systems indicates that MEG drilling fluid system has evident advantages in cave in preventing, lubricity, solid carry capacity and formation damage controlling. The MEG drillling fluid system developed in laboratory is tested in Daqing Oil Field. The laboratory experiment and on-site trial show that the MEG drilling fluid system is stable in rheological property and can carry cuttings and clean wellbore effectively. Its lubricity is excellent and it can stabilize the borehole wall in a good condition. The MEG drilling fluid also can control formation damage and do no harm to environment. The above proves that MEG drilling fluid system is a qualified one to horizontal well of Daqing Oil Field.更多还原